KCC Quizzes AQQ303 about the radius of a circle
1. Quote of the month: "When I die, I want to die like my grandfather who died peacefully in his sleep. Not screaming like all the passengers in his car" - Will Rogers
2. Quiz AQQ304 about finding the radius of a circle
Good luck, and try to be
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August Monthly Blog Quiz! Read the blog, take the quiz, and you could win a gift card
Important: Read the blog first . The quiz questions are all based on the content of the blog:
Stay in the loop and win! Read the blog Current Output Driving Industrial Loops , then take our quick five-question quiz for a chance to win a gift card
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AD536A
Production
The AD536A is a complete monolithic integrated circuit that performs true rms-to-dc conversion. It offers performance comparable or superior to that of...
Datasheet
AD536A on Analog.com
AD637
Production
The AD637 is a complete, high accuracy, rms-to-dc converter that computes the true rms value of any complex waveform. It offers performance that is unprecedented...
Datasheet
AD637 on Analog.com
I need to measure the true RMS voltage of a Sine wave with a DC offset of two different high voltage power supplies (PS1 and PS1).
PS1 DC offset: -6600 VDC nominal
PS2 DC offset: -9300 VDC nominal
Sine wave: 8.98 V peak relative to DC offset of PS1 or PS2.
Any ideas on how to employ a device such as the AD536A or AD637 to achieve this would be greatly appreciated.
Thanks for the question Thomas. The measurement of rms and extracting its dc image is pretty easy, the challenge is the DCHV. How does one effect any sort of a measurement in such an environment?
Back in my ham radio days we used to build transmitters with large cylindrical ceramic capacitors called 'door-knob' capacitors. After a quick search, I see these are still available in some pretty hefty voltage ratings so I would likely start there. You didn't specify the frequency of the sine wave, and whatever that will have to be considered in your choice of isolation media.
Another way to isolate a large dc voltage would be to use a transformer, keeping in mind that the transformer needs to be appropriately insolated. The old TV 'flyback' transformers from years ago would be a good place to start.
After the isolation, the rest should be easier. You would need to decide how much error is acceptable, whether to use a buffer or not, etc. If you go the capacitor route, you can use a combination of straightforward divider and reactance based equations to 'reverse-calculate' coupling capacitor value, etc, etc.
Necessity is indeed the mother of all inventions.
Best of luck!!
js
